ACTA

Structural Study, Mössbauer Spectra and Electrical Properties of R₅Fe₆Sn₁₈ (R = Tm, Lu) Compounds

I. Shcherba^a, L. Romaka^a, A. Skoblik^b, B. Kuzel^a, H. Noga^c, L. Bekenov^b, Yu. Stadnyk^a, P. Demchenko^a, A. Horyn^a
^aIvan Franko L'viv National University, Kyryla and Mefodiya Str. 6,8, 79005 L'viv, Ukraine
^bInstitute for Metal Physics, NAS of Ukraine, Vernadskogo Str. 36, 03142 Kyiv, Ukraine
^cInstitute of Technology, Pedagogical University, Podchorążych 2, 30-084 Cracow, Poland

Received: October 26, 2018; revised version February 18, 2019; in final form February 24, 2019

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Ternary intermetallic R₅Fe₆Sn₁₈ (R = Tm, Lu) compounds have been synthesized from the elements by arc melting, annealed at 670 K and characterized by X-ray powder diffraction and energy dispersive X-ray analyses. Performed structure refinements have shown that they crystallize in the cubic Tb₅Rh₆Sn₁₈ structure type (space group Fm-3m, a=13.55399(4) Å, a=13.53243(5) Å for Tm and Lu compounds, respectively). Using ⁵⁷Fe Mössbauer spectroscopy it has been found that the magnetic state of the Fe atoms in the Tm₅Fe₆Sn₁₈ and Lu₅Fe₆Sn₁₈ stannides is paramagnetic. The value of the isomer shifts for Lu₅Fe₆Sn₁₈ and Tm₅Fe₆Sn₁₈ is positive relative to pure Fe. The ⁵⁷Fe Mössbauer spectra for Lu₅Fe₆Sn₁₈ and Tm₅Fe₆Sn₁₈ stannides have shown that the quadrupole splitting for the Fe position (24e) have magnitudes of 0.43 and 0.45 mm/s, respectively. The similarity of these values is consistent with a qualitative crystal structure analysis. The examined Tm₅Fe₆Sn₁₈ and Lu₅Fe₆Sn₁₈ compounds have been found to be characterized by metallic-like conductivity and high values of electrical resistivity (672.9 μΩ cm, 623.8 μΩ cm at 300 K for Tm and Lu, respectively).

DOI:10.12693/APhysPolA.136.158
topics: intermetallics, quadrupole splitting, Mössbauer spectra, electrical resistivity